The disclosure concerns a method for detecting passages by vehicles at a virtual gantry in a road user charging system and a system for conducting said method.
Systems and methods for automatic controlling passages of objects, typically vehicles, into and/or out from certain geographic areas have been developed during the recent decades, and systems and methods based on Global Navigation Satellite Systems (GNSS) technology are prevailing.
Satellite based road tolling systems are rapidly growing in number due to their versatility and flexibility. It allows for an advanced time/distance/place concept where policy makers can adjust price and tolling zones to best fit their objectives. Non-repudiation of the tolling statement is a very important aspect of the toll system. This includes both proving that the toll statement is genuine and proving that the system correctly identifies vehicles passing virtual gantries.
Even if the average performance and availability of GNSS systems today are very good, there will still be situations where the tolling system may be mislead by erroneous position estimates from the GNSS system. In particular in geographical areas where parts of the sky are obstructed by natural or man-made objects, this may be of great concern.
GNSS based tolling is described by international standards. Of most relevance to the herein disclosure is ISO 17573 Electronic Fee Collection—Systems architecture for vehicle-related tolling and ISO 12855 Electronic Fee Collection—Information exchange between service provision and toll charging. The European Union is working towards a common European interoperable system for tolling where road users have On Board Unit (OBU) and a contract with one home toll operator enabling pan-European roaming where foreign toll charges are invoiced through the home toll operator. This is known as the EETS directive, Directive (2004/52/EC) of the European Parliament and of the Council of 29 Apr. 2004 on the interoperability of electronic road toll systems in the Community. Furthermore, the European Commission Decision (2009/750/EC) of 6 Oct. 2009 on the definition of the European Electronic Toll Service and its technical elements, puts this into effect.
A satellite based road tolling system comprises three main physical elements: 1) The satellites 2) vehicles equipped with OBUs observing signals from the satellites and 3) a so-called back office.
A virtual gantry is a road charging point equivalent to a traditional road charging toll gantry, but normally defined virtually on a map for GNSS road tolling purposes.
The most typical use of such systems is for tolling, where each vehicle owner pays a certain fee for use of the road at passage of a virtual gantry. In general there are two kinds of errors encountered with the use of such systems, one being a false registration of a passage, the other being missed recognition of a passage that actually occurred. Additionally, the detection may erroneously be attributed to a wrong location or a wrong time. All errors may result in lower user confidence in the system and increased operational costs.
WO 2011158038 A1 teaches a method for detecting whether a path has been followed by an object, comprising the steps of receiving position data for the object at timed intervals, determining whether the object has followed the path by detecting a crossing, by the object, of at least one virtual gantry, the virtual gantry defined by a line segment in space crossing the path. Further optional validation checks for each gantry crossing are described, including the detection of the crossing of a number of virtual gantries, in an expected sequence, and over expected distances in an expected direction. A system for carrying out the method is also disclosed.
EP publication 1 696 208 (A1) describes a method and a system by which coordinates are acquired, e.g. by a GPS receiver, and compared with stored data including a definition of an area, or ‘virtual gantry’, which is defined by a polygon progression. The area lies in a position coordinate system, and the coordinates of the area match the coordinates of a geographic region. The area is provided with an attribute in the form of an orientation. At least one parameter derived from the position coordinates of the vehicle is compared with the orientation of the area. An independent claim is included for a system for detecting vehicles in a geographic region.
U.S. Pat. No. 7,324,017B2 describes a process for determining travel through at least one toll road section by at least one vehicle by means of a position determination system which is set up to determine the current position of the at least one vehicle, whereby positions of the at least one vehicle are compared with the position of at least one reference point characteristic for an entrance to a toll road section, whereby the orientation of the vehicle is determined within a specifiable region about the entrance, whereby it is determined whether the orientation determined agrees within a specifiable tolerance range with the orientation characteristic of entry onto the toll road section.
US 2012265430 A1 teaches a method for detecting a boundary crossing of an object, the movement of which being represented by a sequence of positions on a digital road map with vectorized road segments and at least one boundary. The method comprises determining an intersection of the boundary with a road segment and a reference direction in the orientation of this road segment, successively projecting vectors, each determined between one of the positions and the intersection point, onto the reference direction, in order to obtain a sequence of projections, and detecting a boundary crossing if a change of direction or sign occurs in the sequence of projections. EP 1811480 A1 concerns an automatic charging system for charging a vehicle for using infrastructure delimited by a boundary during a charging period, based on GNSS location. The system comprises i) an onboard receiver (OBU) which, in addition to providing position information, provides additional information relating to the error that can be expected in said position consisting of a health flag and an RPL (Radial Protection Level), i.e. the amount limiting the horizontal position error according to one direction and with a probability equal to a known value, ii) a detection module determining that the vehicle is within the boundary at a moment when all the delimited point of a region comprised by a circle of radius RPL centred on said position are within the boundary, and iii) a charging module using the result of the detection module to determine that the vehicle has used the infrastructure during the charging period in question. EP 1811480 also concerns a method of analysis and design of such charging system.
In spite of the efforts to provide and improve systems like those described above, there is still a need, in particular in relation to vehicle surveillance, for methods and systems related to surveillance and position detection of vehicles in a GNSS system, ensuring higher reliability, resulting in lower rates of missed recognition and lower rates of erroneous detections than do existing systems and methods.